I have some components (one is an extension of a Container and one an extension of a Panel) that I had linked into a viewport that was using a border layout. After the project was upgraded, it no longer let's me specify a 'region' property for the linked classes (using an alias as the link). Then the border layout complains that there is no center region. I added a custom property called 'region' to the link and it seems to have fixed it, but I think you should not have to create a custom property for that.